Rare Disease Report

Should Second-line Aplastic Anemia Drug Be a First-line Option?

APRIL 20, 2017
James Radke

Promacta (eltrombopag) is currently approved as second-line therapy for patients with severe aplastic anemia who have had an insufficient response to immunosuppressive therapy. A new study published in the New England Journal of Medicine would indicate that eltrombopag should be part of the first-line therapy for this rare disease in combination with immunosuppressive therapy.
The study by Townsley et al was a phase 1/2 study in which 92 patients with aplastic anemia given immunosuppressive therapy who were enrolled in 1 of 3 treatment cohorts:
1.     received eltrombopag from day 14 to 6 months
2.     received eltrombopag from day 14 to 3 months
3.     received eltrombopag from day 1 to 6 months


The primary outcome was complete hematologic response at 6 months. Secondary end points included overall response, survival, relapse, and clonal evolution to myeloid cancer.


The rate of complete response at 6 months was 33% in cohort 1, 26% in cohort 2, and 58% in cohort 3. The overall response rates at 6 months were 80%, 87%, and 94%, respectively.


Table: Efficacy Outcomes

 Cohort  Eltrombopag treatment Complete
Day 14 to 6 months
Day 14 to 3 months
Day 1 to 6 months


 “The addition of eltrombopag to immunosuppressive therapy was associated with markedly higher rates of hematologic response among patients with severe aplastic anemia than in a historical cohort,” concluded the authors.

In a recent news release, Vasant Narasimhan, Global Head, Drug Development and Chief Medical Officer, Novartis noted, "Eltrombopag is the  only thrombopoietin receptor agonist to be used in the second-line treatment of SAA, and these results from the NIH study now show its potential as a first-line treatment, which we look forward to discussing with health authorities."

About Aplastic Anemia

Aplastic anemia is a very rare but serious blood disorder where the bone marrow fails to make enough blood cells. The exact cause of the disease is unknown, but most cases of severe aplastic anemia are believed to be triggered by an autoimmune reaction.

Severe aplastic anemia can often be treated with immunosuppressive drug regimens or allogeneic stem cell transplantation. However, 20-40% of patients without transplant options do not respond to immunosuppressive therapies. Approximately 40% of patients who don’t respond to initial immunosuppressive therapy die from infection or bleeding within 5 years of their diagnosis. Those patients can now be treated with Promacta. At present, no other orphan drug is approved for aplastic anemia.


Townsley DM, Scheinberg P, Winkler T, et al.  Eltrombopag Added to Standard Immunosuppression for Aplastic Anemia N Engl J Med. 2017; 376:1540-1550 DOI: 10.1056/NEJMoa1613878


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